qmp-commands: move 'chardev-add' doc to schema

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

docs/qmp-commands.txt

@@ -1252,34 +1252,6 @@ Example:
 -> { "execute": "query-tpm-types" }
 <- { "return": [ "passthrough" ] }
 
-chardev-add
-----------------
-
-Add a chardev.
-
-Arguments:
-
-- "id": the chardev's ID, must be unique (json-string)
-- "backend": chardev backend type + parameters
-
-Examples:
-
--> { "execute" : "chardev-add",
-     "arguments" : { "id" : "foo",
-                     "backend" : { "type" : "null", "data" : {} } } }
-<- { "return": {} }
-
--> { "execute" : "chardev-add",
-     "arguments" : { "id" : "bar",
-                     "backend" : { "type" : "file",
-                                   "data" : { "out" : "/tmp/bar.log" } } } }
-<- { "return": {} }
-
--> { "execute" : "chardev-add",
-     "arguments" : { "id" : "baz",
-                     "backend" : { "type" : "pty", "data" : {} } } }
-<- { "return": { "pty" : "/dev/pty/42" } }
-
 chardev-remove
 --------------